Guest

You will need the controller for it. I think it is the Mv Controller. If you do not have one you can kiss your tank goodbye !
The 'bio balls' are called Deniballs. Northlands pets has one or two running.

The mV Controller is designed for monitoring and controlling the redox potential (or ORP - oxidation-reduction potential) in aquaria. The unit has a broad controlling range from -500 to a +500 mV, and a measuring range from -1000 to +1000 mV. It can be used to control the supply of ozone in salt water aquaria and / or for the control of nitrate removal in anaerobic biological filters (Aqua Medic Nitratereductor). The unit is supplied with a BNC connection for an mV probe. The use of an original Aqua Medic plastic shafted electrode is recommended.

Mekaeel a PH controller is used for a CArx, with regards to a nitrate reductor its up to you but it does not do anything more than reduce nitrates in a system by creating an anaerobic area for the denitrifying bacteria. The same is achieved with a DSB but with a DSB you have the advantage of bio diversity and is a totally natural reduction where nothing much can go wrong. With a nitrate reductor i have heard of horror stories where something goes wrong with the controller and the whole system is wiped out.

Mekaeel, a ph controller controls ph by adding controlled dosses of CO2 to lower and then keep pH at a certain level. This is used in a CArx to keep the Ph low enough to disolve the media in the reactor.

A Nitrate reactor uses a MV controller to keep the redox levels low enough to remove Nitrates. if it goes too low the potential exists for Sulfur dioxide (a poison) being released into the tank.

Unless a very highly fed tank is anticipated, a Nitrate reactor IMO is a rather expensive and unneccesary item.